Protists

Question 1

what is a protist

Answer 1

a group of organisms which are not defined as much by commonality but by exclusion- they are something which is not an animal, plant, fungus of prokaryote

Question 2

give some examples of protists

Answer 2

amoebas
paramecia
parasites
oomycetes

Question 3

when did protists emerge on earth

Answer 3

2 billion years ago = unicellular
750 millions years ago= multicellular

Question 4

give an example of a multicellular protist and explain why they dont fit into any other classification

Answer 4

brown algae/ phaeophyta and kelps
- they produce pigments such as chlorophyll c and fucoxanthin which are different photosynthetic pigments than in plants

Question 5

give an example of a multicellular protist and explain why they dont fit into any other classification

Answer 5

brown algae/ phaeophyta and kelps
- they produce pigments such as chlorophyll c and fucoxanthin which are different photosynthetic pigments than in plants

Question 6

what is rhodophyta

Answer 6

red algae = a multicellular protist containing phycobilin pigments

Question 7

why is coralline algae important

Answer 7

• cement the reefs providing new sites for corals to settle
• food source for alot of species

Question 8

give some examples of unicellular protists

Answer 8

• oomycetes
• parasite plants and fish

Question 9

how are cyanpbacterial blooms prevented by protists

Answer 9

some protists feed on bacteria, feeding on cyanobacteria decreases populatinos therefore release of toxins which deplete oxygen are prevented

Question 10

how are protists used to purify waste water

Answer 10

• team up with aerobic bacteria in the aeration tanks to degrade organic matter
• when all nutrients are gone the protists eat the bacteria producing pure water

Question 11

how are protists unique in structure

Answer 11

• some carry more than one nucleus
• some anaerobic protists do not have a true mitochondira

Question 12

what are the two nucleus which can be found in paramecia and what do they contain

Answer 12

1) macronucleus= conatins many copies of genes needed for growth
2) micronucleus= essential for reproductin as it is the storage site for germline material

Question 13

what is the advantage of having two nuclei

Answer 13

allow paramecium to divide faster as having multiple copies of the same genes means transcription of genes is faster and make proteins faster

Question 14

what is schizogony

Answer 14

a form of asexual reproduction where a cell size increases and the nucleus and other organelles divide repeatedly which eventually ruptures producing tiny cells

Question 15

what is a schizont

Answer 15

a type of cell formed as a result of schizogony

Question 16

what mitchondrion related organelles to anaerobic protists have

Answer 16

1) mitosomes= have no ATP
2) hydrogenosomesw = produce ATP by reactions which generate hydrogen by-product

Question 16

what mitchondrion related organelles to anaerobic protists have

Answer 16

1) mitosomes= have no ATP
2) hydrogenosomesw = produce ATP by reactions which generate hydrogen by-product

Question 17

true or false: mitosomes and hydrogenosomes contain DNA

Answer 17

false - they fully rely on proteins transported from cytosol

Question 18

give the names of the protists which are apart of the phytoplankton

Answer 18

1) coccolithophores
2) diatoms
3) dinoflagellates

Question 19

what is a coccolithophore

Answer 19

unicellular algae which uses co2 for photosynthesis to make calcium carbonate coccolith shells which shed as it grows
they are hihgly reflective

Question 20

how do coccolithophores make their calcium carbonate coccoliths

Answer 20

1) atmospheric co2 enters ocean and converted to organic carbon
2) reacts with sea water forming H2CO3 which dissociates to form carbonate and bicarbonate

Question 21

how do coccolithophores form clouds

Answer 21

1) produce dimethylysulfuniopropionate (DMSP which is converted to dimethylsulfide (DMS)
2) sulphate atcs as a nucleating agent for water vapour which forms droplets and clouds

Question 22

what is a diatom

Answer 22

a unicellular algae which is photosynthetic and abudant in aquatic environments

Question 23

outline the structure of the cell wall of diatoms

Answer 23

made of silicon dioxide which are very tough and resistant
cotains pores to facilitate expsoure to water and co2

Question 24

outline asexual reproduction in diatoms

Answer 24

1) the top shelf of the cell acts as a template for the bottom
2) the new bottom becomes a top and is a template for another bottom
3) the new new bottom becomes a top and another bottom is made, each divison making cell smaller
4) when shell is too small the ell exits the shell undergoes meiosis forming gametes which fuse to form a zygote which grows a new shell

Question 25

what are dinoflagellates

Answer 25

protists with a shell made of cellulose, some of which are photosynthetic and others heterotrophs

Question 26

what is paramecia

Answer 26

a ciliate which use cilia to move around and inhabit pond waters, lakes and soils which also prey on other organisms

Question 27

how do paramecia use cilia

Answer 27

1) cilia aligned in rows and move like whips to propell cell = MOVEMENT

2) use to sweep food into gullet where food is digested in vacuoles and waste leaves via anal pore

Question 28

how can paramecia become toxic to predators

Answer 28

bacterial symbiosis
- swallowing bacteria which produce toxins which the paramecia are resistant to but other species are not

Question 29

what is a plasmodium

Answer 29

a type of protist in the apicomplexa and is the main cause of malaria
- five species
- alternates between two life stages in the vector and host

Question 30

outline the life cycle of the plasmodium in the vector

Answer 30

1) female mosquito feeds o a host infected with malaria and aquires the parasite and exit RBC
2) male and female gametes form zygotes which invade the gut
3) zygotes differenciate into n oocytes which enter the hemolymph
4) oocytes develop into sporozoites and travel to salivary glands

Question 31

outline the plasmodium life cycle in the host

Answer 31

1) sporozoites travel to liver
2) here it can remain dormant or multiply
3) sporozoites mature into schizonts (multinuclated cells)
4) cells enter RBC where they mature into ring shaped forms

Question 32

how do plasmodium parasites avoid being destroyed in the host

Answer 32

1) form knob like structures causing infected cells to adhere to blood vessels to avoid destructin by the spleen
2) RBC dont have lysosomes so cant be digested

Question 33

what are labyrinthulomycetes

Answer 33

aquatic microorganisms which produce a network of filaments which act as tracks for nutients to glide to them

Question 34

what are the two main groups of labyrinthuylomycetes

Answer 34

1) slime nets= grow network of slime tubes containing motile cells
2) thraustochytrids= grow as zoospore producing thalli